/*
* Copyright 2007 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;

namespace iText.Barcodes.Qrcode {
//\cond DO_NOT_DOCUMENT
    internal sealed class MaskUtil {
        private MaskUtil() {
        }

        /// <summary>Apply mask penalty rule 1 and return the penalty.</summary>
        /// <remarks>
        /// Apply mask penalty rule 1 and return the penalty. Find repetitive cells with the same color and
        /// give penalty to them. Example: 00000 or 11111.
        /// </remarks>
        /// <param name="matrix">ByteMatrix to apply the penalty rule to</param>
        /// <returns>the rule 1 penalty</returns>
        public static int ApplyMaskPenaltyRule1(ByteMatrix matrix) {
            return ApplyMaskPenaltyRule1Internal(matrix, true) + ApplyMaskPenaltyRule1Internal(matrix, false);
        }

        /// <summary>Apply mask penalty rule 2 and return the penalty.</summary>
        /// <remarks>
        /// Apply mask penalty rule 2 and return the penalty. Find 2x2 blocks with the same color and give
        /// penalty to them.
        /// </remarks>
        /// <param name="matrix">ByteMatrix to apply the penalty rule to</param>
        /// <returns>the rule 2 penalty</returns>
        public static int ApplyMaskPenaltyRule2(ByteMatrix matrix) {
            int penalty = 0;
            byte[][] array = matrix.GetArray();
            int width = matrix.GetWidth();
            int height = matrix.GetHeight();
            for (int y = 0; y < height - 1; ++y) {
                for (int x = 0; x < width - 1; ++x) {
                    int value = array[y][x];
                    if (value == array[y][x + 1] && value == array[y + 1][x] && value == array[y + 1][x + 1]) {
                        penalty += 3;
                    }
                }
            }
            return penalty;
        }

        /// <summary>Apply mask penalty rule 3 and return the penalty.</summary>
        /// <remarks>
        /// Apply mask penalty rule 3 and return the penalty. Find consecutive cells of 00001011101 or
        /// 10111010000, and give penalty to them.  If we find patterns like 000010111010000, we give
        /// penalties twice (i.e. 40 * 2).
        /// </remarks>
        /// <param name="matrix">ByteMatrix to apply the penalty rule to</param>
        /// <returns>the rule 3 penalty</returns>
        public static int ApplyMaskPenaltyRule3(ByteMatrix matrix) {
            int penalty = 0;
            byte[][] array = matrix.GetArray();
            int width = matrix.GetWidth();
            int height = matrix.GetHeight();
            for (int y = 0; y < height; ++y) {
                for (int x = 0; x < width; ++x) {
                    // Tried to simplify following conditions but failed.
                    if (x + 6 < width && array[y][x] == 1 && array[y][x + 1] == 0 && array[y][x + 2] == 1 && array[y][x + 3] ==
                         1 && array[y][x + 4] == 1 && array[y][x + 5] == 0 && array[y][x + 6] == 1 && ((x + 10 < width && array
                        [y][x + 7] == 0 && array[y][x + 8] == 0 && array[y][x + 9] == 0 && array[y][x + 10] == 0) || (x - 4 >=
                         0 && array[y][x - 1] == 0 && array[y][x - 2] == 0 && array[y][x - 3] == 0 && array[y][x - 4] == 0))) {
                        penalty += 40;
                    }
                    if (y + 6 < height && array[y][x] == 1 && array[y + 1][x] == 0 && array[y + 2][x] == 1 && array[y + 3][x] 
                        == 1 && array[y + 4][x] == 1 && array[y + 5][x] == 0 && array[y + 6][x] == 1 && ((y + 10 < height && array
                        [y + 7][x] == 0 && array[y + 8][x] == 0 && array[y + 9][x] == 0 && array[y + 10][x] == 0) || (y - 4 >=
                         0 && array[y - 1][x] == 0 && array[y - 2][x] == 0 && array[y - 3][x] == 0 && array[y - 4][x] == 0))) {
                        penalty += 40;
                    }
                }
            }
            return penalty;
        }

        /// <summary>Apply mask penalty rule 4 and return the penalty.</summary>
        /// <remarks>
        /// Apply mask penalty rule 4 and return the penalty. Calculate the ratio of dark cells and give
        /// penalty if the ratio is far from 50%. It gives 10 penalty for 5% distance. Examples:
        /// -   0% =&gt; 100
        /// -  40% =&gt;  20
        /// -  45% =&gt;  10
        /// -  50% =&gt;   0
        /// -  55% =&gt;  10
        /// -  55% =&gt;  20
        /// - 100% =&gt; 100
        /// </remarks>
        /// <param name="matrix">Bytematrix to apply the rule to</param>
        /// <returns>the rule 4 penalty</returns>
        public static int ApplyMaskPenaltyRule4(ByteMatrix matrix) {
            int numDarkCells = 0;
            byte[][] array = matrix.GetArray();
            int width = matrix.GetWidth();
            int height = matrix.GetHeight();
            for (int y = 0; y < height; ++y) {
                for (int x = 0; x < width; ++x) {
                    if (array[y][x] == 1) {
                        numDarkCells += 1;
                    }
                }
            }
            int numTotalCells = matrix.GetHeight() * matrix.GetWidth();
            double darkRatio = (double)numDarkCells / numTotalCells;
            return Math.Abs((int)(darkRatio * 100 - 50)) / 5 * 10;
        }

        /// <summary>Return the mask bit for "getMaskPattern" at "x" and "y".</summary>
        /// <remarks>
        /// Return the mask bit for "getMaskPattern" at "x" and "y". See 8.8 of JISX0510:2004 for mask
        /// pattern conditions.
        /// </remarks>
        /// <param name="maskPattern">masking pattern to use</param>
        /// <param name="x">width coordiante</param>
        /// <param name="y">height-coordinate</param>
        /// <returns>the mask bit at that position</returns>
        public static bool GetDataMaskBit(int maskPattern, int x, int y) {
            if (!QRCode.IsValidMaskPattern(maskPattern)) {
                throw new ArgumentException("Invalid mask pattern");
            }
            int intermediate;
            int temp;
            switch (maskPattern) {
                case 0: {
                    intermediate = (y + x) & 0x1;
                    break;
                }

                case 1: {
                    intermediate = y & 0x1;
                    break;
                }

                case 2: {
                    intermediate = x % 3;
                    break;
                }

                case 3: {
                    intermediate = (y + x) % 3;
                    break;
                }

                case 4: {
                    intermediate = (((int)(((uint)y) >> 1)) + (x / 3)) & 0x1;
                    break;
                }

                case 5: {
                    temp = y * x;
                    intermediate = (temp & 0x1) + (temp % 3);
                    break;
                }

                case 6: {
                    temp = y * x;
                    intermediate = (((temp & 0x1) + (temp % 3)) & 0x1);
                    break;
                }

                case 7: {
                    temp = y * x;
                    intermediate = (((temp % 3) + ((y + x) & 0x1)) & 0x1);
                    break;
                }

                default: {
                    throw new ArgumentException("Invalid mask pattern: " + maskPattern);
                }
            }
            return intermediate == 0;
        }

        // Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
        // vertical and horizontal orders respectively.
        private static int ApplyMaskPenaltyRule1Internal(ByteMatrix matrix, bool isHorizontal) {
            int penalty = 0;
            int numSameBitCells = 0;
            int prevBit = -1;
            // Horizontal mode:
            //   for (int i = 0; i < matrix.height(); ++i) {
            //     for (int j = 0; j < matrix.width(); ++j) {
            //       int bit = matrix.get(i, j);
            // Vertical mode:
            //   for (int i = 0; i < matrix.width(); ++i) {
            //     for (int j = 0; j < matrix.height(); ++j) {
            //       int bit = matrix.get(j, i);
            int iLimit = isHorizontal ? matrix.GetHeight() : matrix.GetWidth();
            int jLimit = isHorizontal ? matrix.GetWidth() : matrix.GetHeight();
            byte[][] array = matrix.GetArray();
            for (int i = 0; i < iLimit; ++i) {
                for (int j = 0; j < jLimit; ++j) {
                    int bit = isHorizontal ? array[i][j] : array[j][i];
                    if (bit == prevBit) {
                        numSameBitCells += 1;
                        // Found five repetitive cells with the same color (bit).
                        // We'll give penalty of 3.
                        if (numSameBitCells == 5) {
                            penalty += 3;
                        }
                        else {
                            if (numSameBitCells > 5) {
                                // After five repetitive cells, we'll add the penalty one
                                // by one.
                                penalty += 1;
                            }
                        }
                    }
                    else {
                        // Include the cell itself.
                        numSameBitCells = 1;
                        prevBit = bit;
                    }
                }
                // Clear at each row/column.
                numSameBitCells = 0;
            }
            return penalty;
        }
    }
//\endcond
}
